This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 11 |
| 3 | 122 |
| 4 | 2127 |
| 5 | 50682 |
| 6 | 1528900 |
| 7 | 55742458 |
| 8 | 2381375519 |
| 9 | 116597648906 |
| 10 | 6434959707871 |
| 11 | 395148541757400 |
| 12 | 26718459567126420 |
| 13 | 1972367532078679140 |
| 14 | 157829428196155580220 |
| 15 | 13607551212801836305770 |
| 16 | 1257482733143493065605455 |
| 17 | 123990702648155791823769270 |
| 18 | 12993254659661472801817366105 |